1 Field of the Invention
The invention is related to multicomponent thermoplastic interpenetrating polymer network blends and in particular the use of polymers loaded with suspended particulates as the structure stabilizing phase.
2 Prior Art
Thermoplastic interpenetrating polymer networks (TIPN's) have been developed as is evidenced by U.S. Pat. No. 4,088,626 "Multicomponent Polysulfone-Block Copolymer-Polymer Blends" issued to Gergen et al, May 9, 1978 and U.S. Pat. No. 4,338,227 "Ethylene Copolymer Blends and Adhesives Based Thereon" issued to E. C. Ballard July 6, 1982. Gergen et al discloses a multicomponent polymer blend composition comprising an intimately mixed polysulfone, a selectively hydrogenated monoalkenyl arene-diene block copolymer and at least one dissimilar engineering themoplastic resin. The Non-Newtonian flow behavior of block copolymer permits the blend composition to be stress blended at an elevated temperature to form at least one partial continuous network phase which interlocks with the other polymers. This results in a desired balance of properties of the resultant copolymer-polymer blend. Ballard discloses homogeneous blends of at least two cross-linked ethylene copolymers.
Johnson, in U.S. Pat. No. 3,629,154 discloses a method for making thin, electrically conductive nonporous dispersed phase polymeric film. The essential ingredient of the dispersed phase polymeric film is an ethylene-vinyl acetate copolymer highly loaded with a conductive powder. For processing thin films, polyisobutylene is added to the loaded ethylene-vinyl acetate copolymer to reduce its viscosity.
Takida et al in U.S. Pat. No. 3,976,618 discloses a method for making dispersed phase plastic moldings having improved heat deflection characteristics in which large amounts of talc are dispersed in a hydrolyzed ethylene-vinyl acetate copolymer.
In summary the prior art teaches the use of block copolymers as the network structure stabilizing phase in thermoplastic interpenetrating polymer networks (TIPN's). Specifically, the prior art discloses the use of only a hydrogenated monoalkenyl arene-diene block polymer as the structure stabilizing phase.
Materials, other than the hydrogenated monoalkenyl arene-diene block-copolymers disclosed by the prior art, are known to exhibit Non-Newtonian rheological behavior as required for network structure stabilizing phase of thermoplastic interpenetrating polymer networks. R. S. Ziegebaur, and J. M. Caruther in their paper "Rheological Properties of Dispersions of Fused Silica in Polydimethysilorane" presented at the 53rd Annual Meeting of the Society of Rheology, Louisville Kentucky, October, 1981 disclosed various other homopolymer materials containing dispersed particulates which exhibit the desired Non-Newtonian properties. Additionally James L. White in his article "Rheological Behavior of Highly Filled/Reinforced Polymer Melts, Plastic Compounds January/February 1982" discusses the Non-Newtonian behavior of polymers loaded with particulates.